. >> reporter: a law enforcement source tells cbs news the operator told first responders he applied the brakes but they did not function. >> thousands of people are bracing for a complicated monday morning commute. amtrak, whose trains run along the same rail lines, says delays can be expected. >>> police are blaming icy pavement for a massive chain reaction crash in massachusetts that ruined the trip home from thanksgiving today for a whole lot of people. more than 70 cars piled up along interstate 290 in worcester. authorities say a tractor- trailer fish tailed and crashed, setting off a whole series of other collisions. the wrecks closed both sides of the interstate and sent more than 30 people to the hospital. state police had been urging travelers to stay off the roads and avoid central massachusetts. >>> well, the panda cub at the national zoo now has a name. people voted, and they have chosen bao bao for the 100-day- old panda. >> that's neat. that's what my wife and kids voted for. 00 days marks a big milestone for a baby. surae chinn was there for the celebration and the na